GlossaryKind of term: Manufacturing termChip control
What is chip control?
Chip control is about whether the chip breaks into short pieces or runs on as a long curl, and how chips leave the cut; mainly an issue in turning and drilling.
Chip control covers the shape of the chip formed in cutting, short broken chips or long continuous curls, and getting the chips away from the cut. The Dutch term spaanbreking covers the breaking part only. In turning and drilling the cut is continuous, so a long chip can form and wrap round tool, workpiece or chuck. In milling each tooth interrupts the cut, so the issue there is usually evacuation and recutting of chips.
What does chip control depend on?
Whether a chip breaks depends on the material, the chip thickness and the geometry. Tough materials such as austenitic stainless steel, low-carbon steel, pure aluminium, copper and many plastics give long chips. Free-cutting steel and free-machining grades of aluminium and brass break more easily thanks to additions such as sulphur, lead or bismuth. Feed together with the entering angle sets the chip thickness, depth of cut mainly the chip width; a chip breaker in the insert works within a range of feed and depth of cut that the tool supplier states for each geometry. High-pressure coolant can help break the chip.
How does chip control work in practice?
Poor chip control costs manned time: clearing chips, more stops, a surface damaged by a chip spinning round the workpiece. Running unattended or on a night shift needs reliable chip breaking, alongside other conditions such as tool life and process monitoring. A part in a material that breaks badly can therefore cost more than the same part in free-cutting steel, even at equal machining time; by how much depends on how your estimate treats manned and unattended hours.
What is chip control often confused with?
Chip control is not the same as machinability: chip form is one of the criteria of machinability, alongside tool wear, cutting forces and surface quality. And a chip breaker is not chip evacuation: the breaker shapes the chip, evacuation takes the chips out of the cutting zone and the machine.
Frequently asked questions
Why does the chip wind round my turning tool?
Because the material is tough or feed and depth of cut fall outside the working range of the chip breaker. Another chip breaker, a higher feed, a different depth of cut or high-pressure coolant often helps; some materials stay awkward.
Can a batch run unattended with poor chip control?
Rarely reliably. A long chip can stop the machine, damage the workpiece or obstruct the bar feeder. Unattended hours are only defensible in an estimate once the chip demonstrably breaks with that material and cutting data.
Does chip control count in the price per part?
Indirectly. A material that breaks badly needs an operator at the machine more often and makes unattended running less certain. How much that weighs depends on how you cost manned and unattended hours.